Linear actuator and centrifugal safety device thereof

Abstract

A linear actuator (1) and the centrifugal safety device (50) thereof is disclosed. The safety device (50) includes an outer socket (51) having a stop portion (512) and a first accommodation portion (513), an inner socket (53) having a raised portion (531) and a second accommodation portion (532) and a centrifugal assembly (55) having a centrifugal block (551) and an elastic element (555). The inner socket (53) drives the centrifugal assembly (55) to rotate. If the centrifugal force of the centrifugal block (551) is smaller than the elasticity of the elastic element (555), then the centrifugal block (551) is limited in the second accommodation portion (532) by the elastic element (555), or else the centrifugal block (551) moves into the first accommodation portion (513) and clamped by the raised portion (531) and the stop portion (512).

What is claimed is: 
     
       1. A linear actuator ( 1 ), comprising:
 an actuation body ( 10 ), comprising an electric motor ( 12 ), a lead screw ( 13 ), an outer tube ( 14 ) and a telescopic tube ( 15 ), and the lead screw ( 13 ) being driven by the electric motor ( 12 ) to rotate, and the outer tube ( 14 ) adapted to sheathe the telescopic tube ( 15 ), and the telescopic tube ( 15 ) screwed and transmitted with the lead screw ( 13 ); 
 a release mechanism ( 30 ), adapted to sheathe the lead screw ( 13 ); and 
 a centrifugal safety device ( 50 ), adapted to sheathe the lead screw ( 13 ), and comprising: 
 an outer socket ( 51 ), comprising a cavity ( 511 ), at least one stop portion ( 512 ) disposed in the cavity ( 511 ), and a first accommodation portion ( 513 ) disposed on a side edge of the stop portion ( 512 ); 
 an inner socket ( 53 ), installed in the outer socket ( 51 ), and comprising at least one raised portion ( 531 ) extended from an outer peripheral surface thereof, and a second accommodation portion ( 532 ) disposed on a side edge of the raised portion ( 531 ); and 
 a centrifugal assembly ( 55 ), comprising at least one centrifugal block ( 551 ) and at least one elastic element ( 555 ), and the centrifugal block ( 551 ) movably installed between the first accommodation portion ( 513 ) and the second accommodation portion ( 532 ); 
 wherein, the lead screw ( 13 ) is configured to drive the inner socket ( 53 ) and the centrifugal assembly ( 55 ) to rotate, and when a centrifugal force of the centrifugal block ( 551 ) is smaller than an elastic force of the elastic element ( 555 ), the centrifugal block ( 551 ) is limited in the second accommodation portion ( 532 ) by the elastic element ( 555 ), and the inner socket ( 53 ) rotates in the outer socket ( 51 ); and 
 when the centrifugal force of the centrifugal block ( 551 ) is greater than the elastic force of the elastic element ( 555 ), the centrifugal block ( 551 ) is configured to move into the first accommodation portion ( 513 ) and clamped by the raised portion ( 531 ) and the stop portion ( 512 ), and the inner socket ( 53 ) is linked with the outer socket ( 51 ). 
 
     
     
       2. The linear actuator ( 1 ) according to  claim 1 , further comprising: a retarding spring ( 60 ) binding the outer socket ( 51 ) and comprising a positioning arm ( 61 ), and the actuation body ( 10 ) further comprising a casing ( 11 ), and the positioning arm ( 61 ) fixed to the casing ( 11 ). 
     
     
       3. The linear actuator ( 1 ) according to  claim 1 , wherein the stop portion ( 512 ) and the raised portion ( 531 ) are multiple in number, and each of the stop portions ( 512 ) is a stop block, and each of the raised portions ( 531 ) is a rib. 
     
     
       4. The linear actuator ( 1 ) according to  claim 3 , wherein the centrifugal assembly ( 55 ) is multiple in number, and the centrifugal safety device ( 50 ) further comprises a front cap ( 57 ) and a rear cap ( 59 ) covering two ends of the inner socket ( 53 ) and two ends of each centrifugal assembly ( 55 ) respectively. 
     
     
       5. The linear actuator ( 1 ) according to  claim 4 , wherein the rear cap ( 59 ) comprises a flat attaching surface ( 591 ) disposed therein and abutting against an end of each elastic element ( 555 ). 
     
     
       6. The linear actuator ( 1 ) according to  claim 5 , wherein the centrifugal block ( 551 ) comprises a cross-section substantially in a stepped shape, and a thickness of each of two side ends of the centrifugal block ( 551 ) is smaller than a thickness of a middle section of the centrifugal block ( 551 ), and the centrifugal block ( 551 ) comprises a blind hole ( 555 ) respectively disposed on the two side ends, and the elastic element ( 555 ) comprises a compression spring, and one end of the compression spring is accommodated in the blind hole ( 555 ). 
     
     
       7. The linear actuator ( 1 ) according to  claim 4 , wherein each of the raised portions ( 531 ) comprises a snap slot ( 534 ), and a snap bar ( 592 ) is extended from inside of the rear cap ( 59 ) and embedded in the snap slot ( 534 ). 
     
     
       8. The linear actuator ( 1 ) according to  claim 4 , further comprising: a gasket adapted to sheathe the lead screw ( 13 ) and disposed on a side edge of the front cap ( 57 ). 
     
     
       9. The linear actuator ( 1 ) according to  claim 3 , wherein each of the raised portions ( 531 ) comprises a plurality of radial embedding grooves ( 535 ), and the centrifugal assembly ( 55 B) is multiple in number, and each of the centrifugal blocks ( 551 B) comprises a plurality of another radial embedding grooves ( 553 ), and the elastic element ( 555 B) comprises a C-ring, and the C-rings is engaged with one of the radial embedding grooves ( 535 ) and one of the another radial embedding grooves ( 553 ). 
     
     
       10. The linear actuator ( 1 ) according to  claim 9 , further comprising: a retarding spring ( 60 ), and a convex ring ( 515 ) expanded and extended on an end of the outer socket ( 51 B), and the retarding spring ( 60 ) binding the outer socket ( 51 B) and attached to a side edge of the convex ring ( 515 ). 
     
     
       11. The linear actuator ( 1 ) according to  claim 10 , wherein the retarding spring ( 60 ) comprises a positioning arm ( 61 ), and the actuation body ( 10 ) further comprises a casing ( 11 ), and the positioning arm ( 61 ) is fixed to the casing ( 11 ). 
     
     
       12. The linear actuator ( 1 ) according to  claim 1 , wherein the outer socket ( 51 ) comprises a plurality of positioning bars ( 514 ) extended from an outer peripheral surface thereof, and the outer tube ( 14 ) comprises a plurality of positioning slots ( 141 ) for the positioning bars ( 514 ) to be embedded and fixed. 
     
     
       13. A centrifugal safety device ( 50 ), comprising:
 an outer socket ( 51 ), comprising a cavity ( 511 ), at least one stop portion ( 512 ) disposed in the cavity ( 511 ), and a first accommodation portion ( 513 ) disposed on a side edge of the stop portion ( 512 ); 
 an inner socket ( 53 ), disposed in the outer socket ( 51 ), and comprising at least one raised portion ( 531 ) extended from an outer peripheral surface of the inner socket ( 53 ), and a second accommodation portion ( 532 ) disposed on a side edge of the raised portion ( 531 ); and 
 a centrifugal assembly ( 55 ), comprising at least one centrifugal block ( 551 ) and at least one elastic element ( 555 ), and the centrifugal block ( 551 ) movably disposed between the first accommodation portion ( 513 ) and the second accommodation portion ( 532 ); 
 wherein, the inner socket ( 53 ) is configured to drive the centrifugal assembly ( 55 ) to rotate, and when a centrifugal force of the centrifugal block ( 551 ) is a smaller than an elastic force of the elastic element ( 555 ), the centrifugal block ( 551 ) is limited in the second accommodation portion ( 532 ) by the elastic element ( 555 ), and the inner socket ( 53 ) rotates in the outer socket ( 51 ); 
 when the centrifugal force of the centrifugal block ( 551 ) is greater than the elastic force of the elastic element ( 555 ), the centrifugal block ( 551 ) is configured to move into the first accommodation portion ( 513 ) and clamped by the raised portion ( 531 ) and the stop portion ( 512 ), and the inner socket ( 53 ) and the outer socket ( 51 ) are linked with each other. 
 
     
     
       14. The centrifugal safety device ( 50 ) according to  claim 13 , wherein the stop portion ( 512 ) and the raised portion ( 531 ) are multiple in number, and each of the stop portions ( 512 ) is a stop block, and each of the raised portions ( 531 ) is a rib. 
     
     
       15. The centrifugal safety device ( 50 ) according to  claim 14 , wherein the centrifugal assembly ( 55 ) are multiple in number and the centrifugal safety device ( 50 ) further comprises a front cap ( 57 ) and a rear cap ( 59 ) covering two ends of the inner socket ( 53 ) and two ends of each of the centrifugal assemblies ( 55 ) respectively. 
     
     
       16. The centrifugal safety device ( 50 ) according to  claim 15 , wherein the rear cap ( 59 ) comprises a flat attaching surface ( 591 ) disposed therein and abutting against an end of each of the elastic elements ( 555 ). 
     
     
       17. The centrifugal safety device ( 50 ) according to  claim 16 , wherein the centrifugal block ( 551 ) comprises a cross-section substantially in a stepped shape, and a thickness of each of two side ends of the centrifugal block ( 551 ) is smaller than a thickness of a middle section of the centrifugal block ( 551 ), and the centrifugal block ( 551 ) comprises a blind hole ( 555 ) disposed on the two side ends separately, and the elastic element ( 555 ) comprises a compression spring, and one end of the compression springs is accommodated in the blind hole ( 555 ). 
     
     
       18. The centrifugal safety device ( 50 ) according to  claim 15 , wherein each of the raised portions ( 531 ) comprises a snap slot ( 534 ), and a snap bar ( 592 ) is extended from inside of the rear cap ( 59 ) and embedded in the snap slot ( 534 ). 
     
     
       19. The centrifugal safety device ( 50 B) according to  claim 14 , wherein each of the raised portions ( 531 ) comprises a plurality of radial embedding grooves ( 535 ), and the centrifugal assembly ( 55 ) is multiple in number, and each of the centrifugal blocks ( 551 ) comprises a plurality of another radial embedding grooves ( 535 ), and the elastic element ( 555 B) comprises a C-ring, and the C-rings is engaged with one of the radial embedding grooves ( 553 ) and one of the another radial embedding grooves ( 553 ). 
     
     
       20. The centrifugal safety device ( 50 ) according to  claim 13 , further comprising: a retarding spring ( 60 ) binding the outer socket ( 51 ).